ABB XT7, Руководство по эксплуатации и обслуживанию

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ABB | SACE Tmax XT
Protections | 15 - Additional protections and functions 75 | © 2020 ABB | 1SDH001821A1002 - ECN000135670
15 - Additional protections and functions
Introduction Some protections have additional functions which extend their characteristics and performance:
Name Type of protection Page
Thermal Memory overheating of the cables 75
Zone selectivity management of trip commands in a network of circuit-breakers 75
Blocks blocking of protection on the basis of programmable events 78
Startup different thresholds on the basis of monitoring thresholds 78
Current thresholds Current control with programmable thresholds 83
Programmable
Commands
Programmable commands with trip unit events or statuses 84
Installation of accessory modules allows the respective functions to be activated:
Name Type of protection Page
Gext External earth fault with adjustable delay 79
Rc Residual current 82
Synchrocheck Synchronism between two independent voltage sources 84
MDGF Modified differential ground fault 80
Thermal Memory Protection
The function, which is available for L and S protections, allows overheating in the cables connected to the
circuit-breaker to be prevented: in the case of trips within brief intervals, the unit considers the time between
commands and the entity of the faults so as to reduce opening time.
IMPORTANT: for the S protection the function can be activated if the selected curve
is time-dependent.
NOTE: the function also reduces the trip time in the case of overloads which have
not led to the open command (longer than 100ms)
S, S2, I, 2I, MCR, G, Gext,
MDGF zone selectivity
Protection
The function, which can be activated for S, S2, I, 2I, MCR, G, Gext and MDGF protections (if available and
enabled), allows several devices belonging to the same installation (including Ekip Touch) to be interconnected,
so as to handle trip commands in the best possible way in the case of S, S2, I, 2I, MCR, G, Gext and MDGF
protections.
The function allows the devices to be coordinated so that, if a fault occurs:
• the device nearest to the fault trips
• the other devices are blocked for a programmable time
NOTE: connection can be made between ABB devices that have the zone selectivity function
Characteristics
Ekip Touch has five selectivity connections, located on the rear connectors of the CB:
Name Type Description Connection
Szi Input S, S2, I, 2I and MCR protection selecitivity input From devices on the load side
Szo Output S, S2, I, 2I and MCR protection selecitivity output To devices on the supply side
Gzi Input G, Gext and MDGF protection selectivity input From devices on the load side
Gzo Output G, Gext and MDGF protection selectivity output To devices on the supply side
Szc Common Common connection of selectivity network The entire selectivity network
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